Oracle 18c

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CREATE TABLE D_DEPARTAMENTO
  (ID_DEPARTAMENT NUMBER(10,0)
     GENERATED BY DEFAULT ON NULL AS IDENTITY
       MINVALUE 1
       MAXVALUE 9999999999999999999999999999
       INCREMENT BY 1
       START WITH 1
       CACHE 20
       NOORDER
       NOCYCLE
       NOKEEP
       NOSCALE
     NOT NULL ENABLE)
CREATE OR REPLACE FUNCTION GET_COLUMN_SEQUENCE_NAME(pinTable_name  IN VARCHAR2,
                                                    pinColumn_name IN VARCHAR2)
  RETURN VARCHAR2
AS
  lData_default  LONG;
  s              VARCHAR2(32767);
BEGIN
  SELECT DATA_DEFAULT
    INTO lData_default
    FROM USER_TAB_COLS
    WHERE TABLE_NAME = pinTable_name AND
          COLUMN_NAME = pinColumn_name;

  s := SUBSTR(lData_default, 1, 32767);

  RETURN SUBSTR(s, 1, INSTR(s, '.', -1)-1);
END GET_COLUMN_SEQUENCE_NAME;
/

CREATE OR REPLACE FUNCTION RESET_SEQUENCE(pinSequence    IN VARCHAR2,
                                          pinStart_value IN NUMBER DEFAULT 1,
                                          pinIncrement   IN NUMBER DEFAULT 1)
  RETURN NUMBER
AS
  nVal  NUMBER;
BEGIN
  -- Get the next value from the sequence

  EXECUTE IMMEDIATE 'SELECT ' || pinSequence || '.NEXTVAL ' ||
                    '  FROM DUAL'
    INTO nVal;
  
  -- Change the sequence so it decrements or increments to the desired
  -- start value the next time NEXTVAL is invoked.
  
  EXECUTE IMMEDIATE 'ALTER SEQUENCE ' || pinSequence ||
                    '  INCREMENT BY ' || (nVal - (pinStart_value - pinIncrement)) * -1 ||
                    '  MINVALUE 0';

  -- Decrement/increment the sequence to the desired start value

  EXECUTE IMMEDIATE 'SELECT ' || pinSequence || '.NEXTVAL ' ||
                    '  FROM DUAL'
    INTO nVal;
  
  -- Reset the sequence so it uses the desired "increment-by"
  
  EXECUTE IMMEDIATE 'ALTER SEQUENCE ' || pinSequence ||
                    '  INCREMENT BY ' || pinIncrement ||
                    '  MINVALUE 0';
  
  RETURN 1;
EXCEPTION
  WHEN OTHERS THEN
    DBMS_OUTPUT.PUT_LINE('RESET_SEQUENCE : ' || SQLCODE || ' ' || SQLERRM);
DECLARE
  strSequence_name  VARCHAR2(32767);
  nVal              NUMBER;
  nReset            NUMBER;
BEGIN
  strSequence_name := GET_COLUMN_SEQUENCE_NAME('D_DEPARTAMENTO', 'ID_DEPARTAMENT');
  DBMS_OUTPUT.PUT_LINE('strSequence_name = ''' || strSequence_name || '''');

  EXECUTE IMMEDIATE 'SELECT ' || strSequence_name || '.NEXTVAL FROM DUAL'
    INTO nVal;
  DBMS_OUTPUT.PUT_LINE('nVal = ' || nVal);

  EXECUTE IMMEDIATE 'SELECT ' || strSequence_name || '.NEXTVAL FROM DUAL'
    INTO nVal;
  DBMS_OUTPUT.PUT_LINE('nVal = ' || nVal);

  EXECUTE IMMEDIATE 'SELECT ' || strSequence_name || '.NEXTVAL FROM DUAL'
    INTO nVal;
  DBMS_OUTPUT.PUT_LINE('nVal = ' || nVal);

  EXECUTE IMMEDIATE 'SELECT ' || strSequence_name || '.NEXTVAL FROM DUAL'
    INTO nVal;
  DBMS_OUTPUT.PUT_LINE('nVal = ' || nVal);

  nReset := RESET_SEQUENCE(strSequence_name, 10, 2);
  DBMS_OUTPUT.PUT_LINE('nReset = ' || nReset);

  EXECUTE IMMEDIATE 'SELECT ' || strSequence_name || '.NEXTVAL FROM DUAL'
    INTO nVal;
  DBMS_OUTPUT.PUT_LINE('nVal = ' || nVal);

  EXECUTE IMMEDIATE 'SELECT ' || strSequence_name || '.NEXTVAL FROM DUAL'
    INTO nVal;
  DBMS_OUTPUT.PUT_LINE('nVal = ' || nVal);

  EXECUTE IMMEDIATE 'SELECT ' || strSequence_name || '.NEXTVAL FROM DUAL'
1 rows affected

dbms_output:
strSequence_name = '"FIDDLE_DOMZWZHLIQTSJKRAMIBH"."ISEQ$$_299576"'
nVal = 1
nVal = 2
nVal = 3
nVal = 4
RESET_SEQUENCE : -32793 ORA-32793: cannot alter a system-generated sequence
nReset = 0
nVal = 6
nVal = 7
nVal = 8
nVal = 9
RESET_SEQUENCE : -32793 ORA-32793: cannot alter a system-generated sequence
nReset = 0
nVal = 11
nVal = 12
nVal = 13
nVal = 14